Free Fields and Their Quantization

Abstract

Although in the later chapters in this book we will mainly use a mean-field approximation, which amounts to using classical fields, we will have to consider from time to time production and decay rates of particles that can be understood only in the framework of quantum field theory. This chapter therefore contains an introduction into quantum field theory with a fairly comprehensive treatment of the quantization of free fields. A last section then presents a short summary of the calculation of transition rates in quantum field theory and their connection to Feynman graphs that we will sometimes use in later chapters to facilitate the qualitative understanding of physical processes.